Clang: Fix local references for operator arguments

Workaround for wrong cursor annotated by Clang.

Use clang_getCursor in case of the variable used as
operator argument to get the proper cursor.

Task-number: QTCREATORBUG-20966
Change-Id: Idb195bffc2296f3fae27595cf9c43c9e6b2c5cd0
Reviewed-by: Marco Bubke <marco.bubke@qt.io>

src/tools/clangbackend/source/clangreferencescollector.cpp

@@ -43,8 +43,15 @@ namespace {
 class ReferencedCursor
 {
 public:
-    static ReferencedCursor find(const Cursor &cursor)
+    static ReferencedCursor find(const Cursor &cursor, const CXToken &token)
     {
+        if (cursor.spelling().startsWith("operator")
+                && clang_getTokenKind(token) == CXToken_Identifier) {
+            // We are actually inside operator, use clang_getCursor to return a proper cursor instead.
+            return find(clang_getCursor(cursor.cxTranslationUnit(),
+                                        clang_getTokenLocation(cursor.cxTranslationUnit(), token)),
+                        token);
+        }
         // Query the referenced cursor directly instead of first testing with cursor.isReference().
         // cursor.isReference() reports false for e.g. CXCursor_DeclRefExpr or CXCursor_CallExpr
         // although it returns a valid cursor.
@@ -194,7 +201,7 @@ bool ReferencesCollector::checkToken(unsigned index, const Utf8String &identifie
         return false;
 
     { // For debugging only
-//        const SourceRange range = clang_getTokenExtent(m_cxTranslationUnit, token);
+//        const SourceRange range{m_cxTranslationUnit, clang_getTokenExtent(m_cxTranslationUnit, token)};
 //        const uint line = range.start().line();
 //        const ClangString spellingCs = clang_getTokenSpelling(m_cxTranslationUnit, token);
 //        const Utf8String spelling = spellingCs;
@@ -202,7 +209,7 @@ bool ReferencesCollector::checkToken(unsigned index, const Utf8String &identifie
     }
 
     const Cursor currentCursor(m_cxCursors[static_cast<int>(index)]);
-    const ReferencedCursor candidate = ReferencedCursor::find(currentCursor);
+    const ReferencedCursor candidate = ReferencedCursor::find(currentCursor, token);
 
     return candidate.usr() == usr;
 }
@@ -217,7 +224,7 @@ ReferencesResult ReferencesCollector::collect(uint line, uint column, bool local
 
     const Cursor cursorFromUser = m_cxCursors[static_cast<int>(index)];
 
-    const ReferencedCursor refCursor = ReferencedCursor::find(cursorFromUser);
+    const ReferencedCursor refCursor = ReferencedCursor::find(cursorFromUser, m_cxTokens[index]);
     const Utf8String usr = refCursor.usr();
     if (usr.isEmpty())
         return result;

tests/unit/unittest/clangreferencescollector-test.cpp

@@ -463,6 +463,54 @@ TEST_F(ReferencesCollector, ArgumentToFunctionLikeMacro)
     ASSERT_THAT(actual, expected);
 }
 
+TEST_F(ReferencesCollector, OverloadedBraceOperatorArgument)
+{
+    const ReferencesResult expected {
+        true,
+        {createSourceRange(171, 7, 1),
+         createSourceRange(172, 7, 1),
+         createSourceRange(172, 12, 1),
+         createSourceRange(173, 7, 1),
+         createSourceRange(173, 10, 1)},
+    };
+
+    const ReferencesResult actual = getReferences(172, 7);
+
+    ASSERT_THAT(actual, expected);
+}
+
+TEST_F(ReferencesCollector, OverloadedParenOperatorSecondArgument)
+{
+    const ReferencesResult expected {
+        true,
+        {createSourceRange(171, 7, 1),
+         createSourceRange(172, 7, 1),
+         createSourceRange(172, 12, 1),
+         createSourceRange(173, 7, 1),
+         createSourceRange(173, 10, 1)},
+    };
+
+    const ReferencesResult actual = getReferences(173, 10);
+
+    ASSERT_THAT(actual, expected);
+}
+
+TEST_F(ReferencesCollector, OverloadedOperatorsArgumentsFromOutside)
+{
+    const ReferencesResult expected {
+        true,
+        {createSourceRange(171, 7, 1),
+         createSourceRange(172, 7, 1),
+         createSourceRange(172, 12, 1),
+         createSourceRange(173, 7, 1),
+         createSourceRange(173, 10, 1)},
+    };
+
+    const ReferencesResult actual = getReferences(171, 7);
+
+    ASSERT_THAT(actual, expected);
+}
+
 std::unique_ptr<const Data> ReferencesCollector::data;
 
 void ReferencesCollector::SetUpTestCase()

tests/unit/unittest/data/references.cpp

@@ -157,3 +157,18 @@ int functionLikeMacro(int foo)
 {
     return BAR(foo);
 }
+
+template<class T>
+class Container
+{
+public:
+    T &operator[](int); T &operator()(int, int);
+};
+
+int testOperator() {
+  Container<int> vec;
+
+  int n = 10;
+  vec[n] = n * 100;
+  vec(n, n) = 100;
+}